In a manufacturing process of a semiconductor device, functional elements such as a transistor element, wiring, a resistor element, a capacitor element and the like are formed by forming and processing a thin film on a semiconductor substrate. As a method of forming the thin film on the semiconductor substrate, a chemical vapor deposition (CVD) method, a physical vapor deposition (PVD) method, an atomic layer deposition (ALD) or the like are used. In addition, a method such as a reactive ion etching (RIE) method is used as a method of processing the thin film. In addition, in the manufacturing process of the semiconductor device, a surface treatment process such as a plasma treatment or the like are performed in addition to forming and processing the thin film.
A stage for supporting the semiconductor substrate is arranged in the apparatus used for the film formation, processing, and surface treatment steps described above. The stage not only supports the semiconductor substrate but also includes a function for adjusting the temperature of the semiconductor substrate according to each processing step. The stage is arranged with a heating mechanism in order to adjust the temperature as described above. In particular, ceramic heaters (heater units) configured of metal or ceramics are widely used as a heating mechanism in the semiconductor apparatus described above.
In the film formation, processing and surface treatment steps described above, the quality of the thin film, the processed shape and the surface state are sensitively changed depending on the temperature of the substrate. Therefore, a high temperature in-plane uniformity is required for the heater unit described above. The semiconductor apparatus used in the process described above has a different chamber structure and electrode structure according to the characteristics required for each process. Because of these differences in structure, in-plane uniformity of the substrate temperature deteriorates due to heat radiation from the substrate placed in the chamber into the chamber atmosphere and heat radiation transferred from the substrate to the stage on which the substrate is placed. In addition, in an apparatus which has a plasma mechanism, the in-plane uniformity of the substrate temperature deteriorates due to the effects of the plasma density in the chamber.
In order to improve the deterioration of the in-plane uniformity of the substrate temperature, a technique for improving in-plane uniformity of the substrate temperature is disclosed in Japanese Laid Open Patent Publication No. 2006-24433 and Japanese Laid Open Patent Publication No. 2008-251707 for example in which a heating resistor body (heater part) arranged in a heater unit is divided into a plurality of zones and each heater part is independently controlled. In the heater units described in Japanese Laid Open Patent Publication No. 2006-24433 and Japanese Laid Open Patent Publication No. 2008-251707, since a recess part is arranged in a substrate between adjacent zones, the adjacent zones are thermally insulated.
However, as shown in Japanese Laid Open Patent Publication No. 2006-24433 and Japanese Laid Open Patent Publication No. 2008-251707, recess parts between adjacent zones are connected to a space in the chamber (or the atmosphere outside the chamber). Therefore, the insulation efficiency between adjacent zones is affected by the space temperature (or atmospheric temperature) in the chamber. As a result, the insulation efficiency between adjacent zones changes depending on the space temperature in the chamber (or atmospheric temperature), and therefore it is difficult to obtain a stable insulation effect which does not depend on the usage environment. In addition, if the distribution of the heated gas existing in the chamber is biased, in-plane uniformity of the substrate temperature deteriorates.